Abstract: By case study,it described the model construction mechanism of multiple-factor static gray model and built up the GM(0,N)model by mean of deformation monitoring data. The model precision was analysed by case calculation and the trend of dam de-formation were forecasted, thus gained the good forecast precision. Comparing multiple-factor static gray model with regression model, it can be proved the advantage of multiple-factor static gray model in the case of less data. Therefore, it showed that the gray system theory is an effective data processing method for dam deformation analysis.